Electronics > Beginners
ATX (bench) Power Supply Outputting Voltage but not Current
FrankvHoof:
I'm currently trying to create bench power supply (for small projects) from an old ATX-PSU..
However, when I attach a load (I'm using a PS3-controller for testing purposes), I can see Voltage across it, but no current. At first I thought this was because I did not have a load-resistor across the 5V-rail. However, even after adding this resistor, I'm still not seeing any current.
I'm using a Component Pro ATX-300TAF 300W power supply that I pulled from an old PC.
Eventually (when I get it working), it's supposed to hook up to this front panel:
My current test-setup can be seen below. I've tried hooking up my USB-Port (female) to both the 5V StandBy-, and the 5V Active-Rails, to no avail.
Does anybody have any other ideas? (Or has my tinkering already destroyed this PSU?)
ledtester:
How are you measuring current? The PS controller doesn't required a lot, and the panel meter you are using probably won't register anything if the draw is less than 10mA.
How about testing it with another power resistor - e.g. a 10R resistor across the 12V rail, or something that should draw 100s of mA.
FrankvHoof:
I'm measuring current (and voltage) using my cheap chinese digital multimeter (https://bit.ly/2OcfDXE) in series. I've tried it both at my USB-port, and at my load-resistor, but am not seeing any current on either.
When the controller is drawing current (i.e. charging), it's light should come on, and start blinking.
I've also tried hooking up my phone, which doesn't receive any charge either.
Edit: Correction: After fully 'resetting' the PSU, I'm now seeing .5A at my load resistor, but still nothing at my 5V Sb hooked up to the USB
FrankvHoof:
Update: So.. apparently I am getting current...
I can get a led to light: (Both on 5V active & 5V Sb)
(Although sometimes it seems to 'short out' & shutdown when I power it up with the led attached)
However, as soon as I attach something over USB, it doesn't actually power up.
I have tried re-soldering another USB-port (making sure to get the polarity correct, and checking that it's not shorted to the outer sleeve anywhere), to no avail.
I have tried attaching 3 different items:
- A PS3-controller. Apparently these will never charge without handshaking (see https://gaming.stackexchange.com/questions/73919/what-wall-plug-chargers-can-be-used-to-charge-ps3-controllers )
- A mobile phone (Oppo F7). As far as I know, these should charge at 500mA when not handshaking (or 1A when the datalines are shorted?)
- A cheap chinese battery charger. I'm not 100% sure, but I'd guess this doesn't require any handshaking. ( https://www.aliexpress.com/item/32957808873.html )
I currently do NOT have a load-resistor on the 5V-Line (accidentally stripped the leg off of my last 10W resistor, but I DO have one on the 12V line..
Does anybody have any idea as to what might be happening?
Do I require a handshaking-circuit to even power anything?
Edit: it appears to be shorting out sometimes even without anything attached, so I'm guessing it's at least partially broken (and I will be replacing it when I get everything up & running).. However, as I can get it to light a led, it should also be able to power the USB-charger, no? (charger runs at 2.1A max, but I was able to get it to power on a 1A usb wall-plug from a ChromeCast)
mariush:
Do you actually start the power supply?
By default, the psu should only output 5v standby on the mauve wire. The label says maximum 2A on 5v.
You must turn on by shorting the PSON wire to ground (or through a resistor (100ohm or somewhere around that value) resistor )
Should be fairly obvious the psu works because the fan should spin when it's on.
What digital multimeter / display are you using? Some of those can not be powered from the same power supply they're monitoring, the display may need to be powered from separate psu/
Navigation
[0] Message Index
[#] Next page
Go to full version